Waterfast dyes for ink jet recording fluids

Abstract

An ink jet ink composition comprises a liquid vehicle, a dye, and an N-hydroxyalkyl branched polyethyleneimine polymer or an N-hydroxyalkyl diphenylguanidine substituted at about 80% of the available nitrogens. The dye in this ink jet composition decreases the solubility of the ink and, therefore, can be used to formulate waterfast inks for ink jet printers.

We claim: 
     
       1. An ink jet ink composition comprising a liquid vehicle, a dye, and an N-hydroxyalkyl imine substituted at about 80% of the available nitrogens, wherein the N-hydroxyalkyl imine substituted at about 80% of the available nitrogens is selected from the group consisting of branched polyethyleneimine polymer and diphenylguanidine and the branched polyethyleneimine polymer is epicholorohydrin modified. 
     
     
       2. An ink jet ink composition as claimed in claim 1 wherein the N-hydroxyalkyl imine substituted at about 80% of the available nitrogens consists of 3,3-bis-hydroxyethyl- 1,1-diphenylguanidine, substituted at 82% of the available nitrogens. 
     
     
       3. An ink jet ink composition as claimed in claim 1 wherein the N-hydroxyalkyl imine substituted at about 80% of the available nitrogens is present in an amount of from about 1 to about 3 percent by weight. 
     
     
       4. An ink jet ink composition as claimed in claim 1 wherein the dye is water soluble and selected from the group consisting of Direct Dyes, Acid Dyes and Food Dyes. 
     
     
       5. A process for generating images which comprises incorporating into an ink jet printing apparatus the ink composition of claim 1 and forming images by causing the ink to be expelled in droplets onto a substrate, thereby generating an image on the substrate. 
     
     
       6. A process as claimed in claim 5 wherein the ink contains an N-hydroxyalkyl imine substituted at about 80% of the available nitrogens selected from the group consisting of branched polyethyleneimine polymer and diphenylguanidine. 
     
     
       7. A process as claimed in claim 5 wherein the N-hydroxyalkyl imine substituted at about 80% of the available nitrogens consists of 3,3-bis-hydroxyethyl-1,1-diphenylguanidine, substituted at 82% of the available nitrogens. 
     
     
       8. A process as claimed in claim 5 wherein the N-hydroxyalkyl imine substituted at about 80% of the available nitrogens is present in an amount of from about 1 to about 3 percent by weight. 
     
     
       9. A process as claimed in claim 5 wherein the image is generated by a continuous stream ink jet printing process. 
     
     
       10. An ink jet composition as claimed in claim 1 wherein the liquid vehicle is selected from the group consisting of a wetting agent, a biocide, denatured alcohol, deionized water, and mixtures thereof. 
     
     
       11. An ink jet composition as claimed in claim 10 wherein the liquid vehicle is selected from the group consisting of a wetting agent, a biocide, denatured alcohol, deionized water, a corrosion inhibitor, a lower alphatic alcohol, and mixtures thereof. 
     
     
       12. An ink jet composition as claimed in claim 1 further comprising a defoamer. 
     
     
       13. An ink jet composition as claimed in claim 1 wherein the diphenylguanidine is epicholorohydrin modified. 
     
     
       14. A method for formulating modified dyes for ink jet printers, the method comprising the steps of: interacting acid and direct dyes with a hydroxyalkyl product of diphenylguanidine to produce hydroxyalkylated diphenylguanidine modified dyes;   forming a corresponding guanidinium salt of dyes from the interaction;   using the modified dyes to formulate waterfast inks for ink-jet printers, wherein diphenylguanidine reacts with two molecules of epicholorohydrin to form a corresponding dihydroxypropyl guanidine.   
     
     
       15. A method as claimed in claim 14 wherein the acid and direct dyes carry --COOH groups. 
     
     
       16. A method as claimed in claim 14 wherein the acid and direct dyes carry --SO3H groups. 
     
     
       17. A method as claimed in claim 14 wherein hydroxyalkyl diphenylguanidine derivatives groups lower the solubility of the modified dyes in water. 
     
     
       18. A method as claimed in claim 14 wherein the hydroxyalkyl groups enhance the affinity of dye to paper. 
     
     
       19. A method as claimed in claim 14 wherein the modified dyes have some solubility in alcohol. 
     
     
       20. A method as claimed in claim 14 further comprising the step of adding a small percentage of alcohol to aqueous inks to improve drying time. 
     
     
       21. A method as claimed in claim 14 wherein diphenylguanidine reacts with two molecules of ethylene oxide to form a corresponding dihydroxyethyl derivative. 
     
     
       22. A method as claimed in claim 21 wherein the derivative reacts with a dye which can have sulfonic and carboxylic groups to form a corresponding salt. 
     
     
       23. A method as claimed in claim 14 wherein the guanidine reacts with a dye which can have sulfonic and carboxylic groups to form a corresponding guanidinium salt. 
     
     
       24. A method as claimed in claim 14 wherein the guanidinium salt dye is used to formulate waterfast ink jet ink. 
     
     
       25. A method as claimed in claim 14 wherein the diphenylguanidine comprises 1,1-diphenylguanidine. 
     
     
       26. A method as claimed in claim 14 wherein the diphenylguanidine comprises 1,3-diphenylguanidine.